The advantages of building a thermally sound structure are becoming even more important with increasing energy costs. Thermally sound structures prevent heat loss decreasing utility bills and increasing energy efficiency. Standard building methods address the issue but these methods often come at a cost. Structural insulated panels, or SIPs, offer high energy efficiency but are costly. The base cost of these panels is high and their cost escalates with the additional time and labor required to install them. Door and window cutouts require time consuming and toxic foam scooping. Wall erection, panel fitting and field modifications are difficult and require specialized equipment. Wiring and other rough-in systems become complicated. The panel drawings and design-specific manufacturing processes add extra costs and a 1-3 month delay. The structural adhesive has been known to fail when exposed to moisture. Attempts have been made to address these many issues (see, for example, U.S. Pat. Nos. 4,628,650; 4,702,058; 5,771,645; and U.S. Pat. No. 6,308,491 B1, and United States Published Patent Application Nos. 2009/0100781 A1; 2009/0205277 A1; and 2010/0043327). Panel production of SIPs however involves excessive waste, which also drives up the cost. SIP walls are expensive at roughly $8.50/square foot (SF) of wall, or roughly double the cost of a traditionally framed wall.
Traditional wood framing with fiberglass battens or blown-in insulation is prominent and cost-effective at $4.00/SF of wall, but offers a poorly insulated building envelope and allows thermal bridging and air infiltration. Structures built in this manner may meet the threshold thermal requirements of the International Building Code, however owners incur substantially higher utility bills and excessive fuels are spent on climate control.
Traditional wood framing with sprayed urethane insulation offers good thermal performance; however there is thermal bridging across wood stud members. In addition to toxic off gassing, the major drawback of this method is the cost at roughly $7.00/SF of wall.
Non-traditional wood framing methods such as creating double stud walls, wide plates with staggered studs or rigid foam sheathed walls are viable energy efficiency options, however each method has its own drawbacks, thus complicating the building process and the associated engineering. These methods are also cost prohibitive most being priced at greater than $7.00/SF of wall.
Insulated concrete forms (ICFs), concrete block (CMU) or concrete/foam sandwich panels offer solid energy efficiency; however labor, coordination and cost are much more extensive than traditional methods at around $12/SF of wall. Furthermore, concrete wall construction has not found a viable solution to complications arising in electrical and plumbing rough-in phases that follow.
While there are currently viable wall systems in place offering sound thermal performance, these options each entail their own unique set of drawbacks and all are substantially higher priced than the traditional stick-framed structure insulated with fiberglass batting. For these reasons, builders have found little incentive to deviate from the prominent, yet energy-inefficient norm of stick framed construction.
A need remains for a wall panel system that incorporates the advantages of shell framing methods, yet eliminates nearly all of the drawbacks. The wall panel system should be cost-effective, preferably around $5.00/SF of wall, readily available for same day install, easily customizable and able to be erected on-site, integrate seamlessly with traditional framing and meet engineering, building code & local requirements.
All patents, patent applications, provisional patent applications and publications referred to or cited herein, are incorporated by reference in their entirety to the extent they are not inconsistent with the teachings of the specification.